3D pen



FIG. 1 is a front elevational view of a 3D pen showing my new design;

FIG. 2 is rear elevational view thereof.

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a perspective view thereof; and,

FIG. 7 is an exploded perspective view thereof. 

CLAIM The ornamental design for a 3D pen, as shown and described. 